RU2135421C1 - Method of removing one or more metals from water - Google Patents

Abstract

FIELD: biotechnology and ecology. SUBSTANCE: method comprises removing some metals from water by reaction with phosphates resulting from fermentative cleavage of polyphosphate accumulated by one or more microorganisms which are capable of accumulating polyphosphate. Metals being removed include cadmium, lead, uranium, and lanthanum. Bacteria of Acinetobacter genus are used. Microorganisms are cultivated in aerobic conditions. When conditions on anaerobic microorganisms change, accumulated polyphosphate is used. The resulting phosphate ions, while in reaction with metal ions, cause precipitation of metal phosphates. EFFECT: simplified technology of water purification and greater technological safety of process. 7 cl, 15 dwg, 6 tbl

Description

The invention relates to the accumulation of metal and, in particular, it relates to the removal of metals from water containing such metals, for example, for one or more of the following purposes:
(a) water treatment,
(b) recovering metals from water used in washing or in another process, for example, from water used in the processing of precious metal ores, and
(c) the accumulation of heavy metals from water, which is used for soil treatment to remove heavy metals from such soils.

 Earlier in L.E. Macaskie J. Chem. Technol. Biotechnol. 49, 357 - 379 (1990) "Animmobilized cell bioprocess for the removal of heavy metals from liquid flows" proposed the removal of heavy metals using Citrobacter ps., In this method, biomass was cultured using glycerol-2-phosphate to obtain cell biomass in a physiological state suitable for metal removal.

 It was believed that the removal of metals occurs due to the joint presence of metal and glycerol-2-phosphate (C2P) in an amount of up to 5 mM, which is a phosphate donor during the accumulation of metal through immobilized cells. G2P is enzymatically cleaved to glycerol (a source of potential energy for cells) and inorganic phosphate, the outflow of which interferes with the flow of metal and precipitates crystalline heavy metal phosphate. Although this method is effective in removing heavy metals from solution, it has the disadvantage of using expensive glycerol-2-phosphate.

 The aim of the present invention is to provide a methodology in which it is not intended to use such an expensive medium as glycerol-2-phosphate.

 In one aspect, the present invention provides the use of one or more polyphosphate-accumulating microorganisms for the accumulation of polyphosphate, which is then enzymatically cleaved in the presence of water containing one or more metals, to produce phosphate ions that interact with the metal (s) in water to precipitate metal phosphate. Such a metal phosphate may be crystalline or may be mixed with other precipitated species, for example hydroxide.

 In another of its aspects, the present invention provides the use of phosphate ions obtained by cleaving polyphosphate to remove metal (s) from solution by precipitation of metal phosphate (s).

 Metals that lend themselves to the methods of the present invention are those that have phosphates having low solubility in water, for example cadmium, lead, copper, manganese, cobalt, nickel, calcium, yttrium, strontium, uranium, lanthanum, lanthanides, plutonium, americium and neptunium.

 In a preferred method, the polyphosphate-accumulating microorganism is cultured in a culture medium under conditions where the microorganism can synthesize and use adenosine triphosphate (ATP), and then the synthesis / use of ATP is modified so that the microorganism uses polyphosphate as an alternative energy source, which results in the aforementioned phosphate ions, which are then reacted with metal ions to precipitate metal phosphate.

 The microorganism is preferably a polyphosphate accumulating bacterium, and it can be, for example, an Acinetobacter polyphosphate accumulating bacterium. It is known from the work (see Y. Comeau et al., Wat. Res. Vol. 20, N 12, pp. 1511 - 1521) that: (a) certain microorganisms are able to accumulate polyphosphate reserves under aerobic conditions and use such polyphosphate under anaerobic conditions for the production of phosphate, and that: (b) it can be applied to cause biological removal of phosphorus in the treatment of activated sludge by providing anaerobic treatment of the upstream zone of a conventional aerobic process. However, as far as is known, it has never been proposed to use polyphosphate accumulated by such microorganisms as a source of phosphate to remove heavy metals from solution. Thus, the present invention is based on the use of polyphosphate as the main source of phosphate in the accumulation of metal through enzymatically mediated bioaccumulation or biomineralization of the metal.

 A particular example of the known polyphosphate accumulating Acinetobacter bacteria is Acinetobacter calcoaceticus ATCC 23055 (NCIMB 10694). Another example of a known polyphosphate storage microorganism is Klebsiella pneumoniae ATCC 12658 (= NCIMB 8806).

 In the case of Acinetobacter, ATP synthesis / use is possible under aerobic conditions, and a change in the direction of ATP energy use is possible by switching to anaerobic conditions. Under anaerobic conditions, the use of ATP is delayed due to inhibition of ATP synthesis, since it usually occurs under normal (aerobic conditions). However, it is within the scope of the present invention to change the direction of use of ATP by adding a non-binding (mismatched) substance that interferes with the synthesis of ATP, for example 2,4-dinitrophenol or DCCD (dicyclohexylcarbodiimide).

 Preferred bacteria are Acinetobacter sp. W6 and Acinetobacter sp. W9, which are isolated from activated sludge, which will be described later, and which were deposited under the terms of the Budapest agreement "The National Collection of Indastrial and Marine Bacteria Limited" (NCIMB) 23 st. Machar Drive, Aberdeen AB2 1RV, Scotland, under the corresponding new extension numbers NCIMB 40594 and NCIMB 40595 on November 5, 1993.

Suitable indicators of these bacteria (which were observed with growth on nutrient agar Lab M and incubated at 25 ^° C.) were as follows (see end of description).

 It was also found that the present invention does not require the microorganism accumulating polyphosphate, isolated from the environment in which it occurs. In particular, it has been found that activated sludge containing polyphosphate-accumulating microorganisms can be used in the present invention by itself. A suitable type of activated sludge is that which is used in a plant to remove phosphorus ions from effluent (waste) water (for example, by the so-called “Phostrip” or “Phoredox” method before being discharged into the environment.

 It should be appreciated that the techniques of the present invention are based on the supply of phosphorus. Such a supply can be provided at least in part by carefully adding an assimilable source of phosphorus. However, it is understood that the present invention is applicable to the removal of metal (s) from water that already contains an assimilable source of phosphorus in the form of an impurity, but which is not in the form in which it can directly interact with an impurity of metal (s) also present in water, or in which the metal impurity is not in the form in which it can interact with phosphorus.

 The working conditions at the aerobic and anaerobic stages of the method are the usual conditions that are used for aerobic and anaerobic treatments, including the use of microorganisms. However, it is preferable to use low concentrations of nitrate at the anaerobic stage, since the reduction of nitrate to nitrite can replace oxygen and can then inhibit the necessary conversion of polyphosphate to phosphate.

Typically, the temperature is in the range from 0 to 36 ^o C, most preferably from 15 to 30 ^o C. The medium used for aerobic cultivation of the microorganism is a suitable nutrient medium containing assimilable carbon, nitrogen, phosphorus and other trace elements necessary for optimal growth. Such an environment may be waste from another process. It is not necessary to use expensive sources of carbon and phosphorus, such as G2P.

 Under anaerobic conditions, it is not necessary to provide such nutrients that are needed only to create appropriate anaerobic conditions by ensuring the absence of dissolved oxygen and oxidized nitrogen (nitrite and nitrate).

 Next will be described a typical method of removing heavy metals from wastewater in accordance with the present invention.

 Typical representatives of polyphosphate-accumulating Acinetobacter sp. Strains are grown aerobically and immobilized on a solid support (e.g., open-cell polyurethane foam, glass beads, sand or gravel type materials) in a bioreactor using an aqueous nutrient medium that is circulated through the bioreactor. Gaseous oxygen is introduced through the supply of compressed air and a device for the destruction of bubbles. The nutrient medium contains fermentation wastes and spent phosphate from wastewater enriched with phosphate as sources of assimilable carbon, nitrogen and phosphorus.

Aerobic treatment is carried out at a temperature of from about 20 ^o C, at a pH of 7.0 for 24 to 48 hours, in order to accumulate polyphosphate.

 After this, the conditions in the bioreactor are switched to anaerobic conditions, when nutrients or assimilated oxygen are not supplied.

 Wastewater containing heavy metals that must be removed is passed through a bioreactor in order to contact with immobilized bacteria containing accumulated polyphosphate.

 Under anaerobic conditions, the bacteria deprived of the supply of ATP and, thus, begin to use accumulated polyphosphate as an energy source. The result of this is that the polyphosphate is enzymatically cleaved to produce a phosphate that interacts with heavy metals to precipitate heavy metal phosphate, thereby removing heavy metals or at least decreasing the concentration of heavy metals in water.

 Then, the bioreactor can be switched back, so that it works under aerobic conditions, so that the method can be carried out cyclically with periodic shutdown to replace the microorganism when it becomes unviable.

 During each anaerobic stage, the microorganism can also produce accumulated carbopolymer, polyhydroxybutyrate (PHB) with an appropriate supply of carbon, which can be used as a source of reserve carbon for growth and to generate ATP to fuel during further accumulation of polyphosphate during the subsequent aerobic cycle.

 The present invention will be described in more detail in the following experiments.

 Description of the drawings.

 FIG. 1a is a graph in which concentrations of lanthanum phosphate ion and lanthanum ion are presented as a function of time during the inorganic deposition of lanthanum phosphate in a cell-free solution.

 FIG. 1b is a graph in which the concentrations of the phosphate ion and the uranyl ion in the solution are presented as a function of time during cultivation in a solution containing no cells.

 FIG. 2a and 2b are diagrams showing the results shown in tables 1 and 2, respectively.

 FIG. 3a is a graph showing the release of phosphate using Acinetobacter calcoaceticus NCIMB 10694, in which the phosphate concentration is expressed as a function of time.

 FIG. 3b is a graph showing the removal of lanthanum using Acinetobacter calcoaceticus NCIMB 10694, in which the concentration of lanthanum is expressed as a function of time.

FIG. 4 is a graph showing the release of phosphate using strain W9 under anaerobic conditions in the presence and absence of La ³⁺ and the removal of lanthanum, in which the phosphate and lanthanum concentrations are expressed as a function of time.

 FIG. 5 is a graph showing lanthanum removal and phosphate release using cell suspensions of strain W6, incubated under anaerobic conditions, in which the phosphate and lanthanum concentrations are presented as a function of time.

 FIG. 6-9 are diagrams showing the results presented below in tables 3-5, respectively.

FIG. 10 and 11 show the concentrations of phosphate and metal, respectively, in the first and second reactors during one aerobic and one anaerobic period for two consecutive days in experiment 8 below, and
FIG. 12 represents an X-ray diffraction spectrum of a sample obtained from the second reactor used in Test 8, as compared to that for pure H ₂ (UO ₂ ) ₂ (PO ₄ ) ₂ • 8H ₂ O.

In the experiments presented below, the following culture media were used:
Wednesday 1 - nutrient medium, g / l
Tris - 6.0
Sodium Acetate - 5.0
(NH ₄ ) ₂ SO ₄ - 1.5
MgSO ₄ • 7H ₂ O - 0.16
CaCl ₂ • 2H ₂ O - 0.08
KCl - 0.6
The solution of trace elements ^a , ml - 1.0
A solution of salts of ferrous iron and EDTA ^b , ml - 0.25
HCl was adjusted to pH 7.1 and the medium was sterilized by autoclaving. The following was sterilized separately and added after cooling:
10% Yeast extract, ml - 1
K ₂ HPO ₄ • 3H ₂ O, g - 0.16
^a solution of trace elements contained, mg / l
ZnSO ₄ • 7H ₂ O - 10
MnCl ₂ • 4H ₂ O - 3
H ₃ BO ₃ - 30
CoCl ₂ • 6H ₂ O - 20
CuCl ₂ • 2H ₂ O, μg - 1
NiCl ₂ • 6H ₂ O - 2
Na ₂ MoO ₄ • 2H ₂ O - 3
^b The solution of ferrous salts and EDTA contained (heptahydrate) iron (II) sulfate and disodium salt of ethylenediaminetetraacetic acid (commercially obtained mixture) 1.0 g / l]
Medium 2 is a nitrogen-limiting nutrient medium.

Similar to medium 1, but contains (per liter) 10 g of sodium acetate and 0.23 g of K ₂ HPO ₄ • 3H ₂ O.

Wednesday 3 - the environment of the aerobic stage, containing, g / l:
Tris - 6.0
Sodium Acetate - 0.36
(NH ₄ ) ₂ SO ₄ - 0.02
MgCl ₂ • 6H ₂ O - 0.03
CaCl ₂ • 2H ₂ O - 0.02
KCl - 0.012
K ₂ HPO ₄ • 3H ₂ O (autoclaved separately) - 0.136
PH 7.1 was adjusted with HCl and the medium was sterilized by autoclaving.

 Wednesday 4 - Wednesday anaerobic stage (final concentration).

MOPS (3- (N-morpholino) propanesulfonic acid), mm:
Buffer solution NaOH pH 7.0 - 40
Citric Acid / Trisodium Citrate Buffer Solution, pH 7.0 - 2
Sodium acetate (sterilized by autoclaving) - 10
In some experiments, MOPS was replaced with Tris / HCl buffer at the same pH and concentration. In experiments with uranyl ions, sodium acetate was replaced with 10 mM ammonium acetate.

Unless otherwise indicated, in all experiments was carried out at 30 ^o C.

 Isolation of microbial strains W6 and W9.

A mixed activated sludge solution was obtained from a Severn Frent wastewater treatment (located in Wimborne, England). A homogeneous suspension of each liquid was prepared and serial dilutions (in sterile saline, 0.85% w / v) were applied to nutrient agar (Difco Laboratiries, Detroit, USA). After 2 weeks of incubation at room temperature (20 ^° C.), colonies with distinctly different morphologies were selected, removed from 10 ^-4 to 10 ^-6 dilutions, and covered with strips until the tone was clean on nutrient agar. After performing Gram and oxidase dye experiments, the isolated microorganism strains (W6 and W9) were tentatively identified using the API 20E and 20 NE identification bands (API system, bio-Merieux, SA, France) as the genus Acinetobacter. The strains W6 and W9 were deposited under the terms of the Budapest Agreement "The National Collection of Industrial and Marine Bacteria Limited (NCIMB) under the corresponding new extension numbers NCIMB 40594 and NCIMB 40595 on November 5, 1993.

 Methods

 (a) Free-cell experiments.

50 ml of the initial culture medium 1 was inoculable and incubated for 1-2 days. 20 ml of it was used to inoculate 2 l of medium 2 and the culture was incubated aerobically with forced aeration of compressed air for 24 to 36 hours. Cells were harvested by centrifugation (4500 rpm, 4 ^° C., 30 minutes). The pop-up (supernatant) was drained and part of it was used to re-suspend the cells. Each suspension was again subjected to centrifugation. The granules of the cells were again resuspended in portions of the floated up, the cell suspensions were combined and cooled on ice before use.

 A mixed cell suspension was used to inoculate medium 4 with and without addition of metal salts, as described in separate experiments. Air or gaseous nitrogen (not containing oxygen) was bubbled through the medium, depending on whether the aerobic or anaerobic conditions were necessary.

 From time to time, 1 ml of the incubation mixture was removed and the cells were rapidly precipitated by centrifugation (12,000 rpm, 5 minutes). The pop-up was analyzed for phosphate and metal content.

 (b) Experiments with immobilized cells.

 Cultures grew to 4 L and were harvested as described for free cell experiments. Cell pellets were weighed, resuspended in 0.85% NaCl, and aliquoted. Cells were immobilized differently in agar-agar or agarose (final concentration 3% w / v, final cell concentration approximately 5% w / v) during the formation, in some experiments, of beads (with an average diameter of 1 mm) in according to the method of Nielson et al. (Eur.). Appl. Microbiol. Biotechnol 17: 319-326), while soybean oil was used for the hydrophobic phase. In other experiments, the gelled cell suspension was placed in a mold and the cured gel was crushed by passing through a steel sieve to obtain pressed particles with a cross-sectional area of 1 mm and a length of up to 10 mm. The gel or bead particles were washed in saline to remove non-immobilized cells and / or adherent oil and placed in a pre-sterilized reactor or column.

 Here they were incubated at alternating anaerobic and aerobic stages (respectively, medium 4 or 3) with or without metal at the anaerobic stage as described below.

 Chemical analyzes.

CuKα излучение.Cadmium and lead were detected by ASV (anodic stripping voltammetry) with a hanging mercury droplet electrode using a Metrohm 693 VA polarographic and voltammetric analyzer. Lanthanum and uranyl were detected by calorimetric determination using a compound of arsenic (III) in an acidic solution (MRTolley, D.Phil. Thesis Univ. Of Oxford. 1993). Phosphate was determined calorimetrically by its interaction with acidified molybdate (Pierpont 1957 Biochem. J. 65: 67-76). Powder X-ray diffraction analysis data were obtained on a Picker Precision diffractometer with an incident beam monochromator (germanium 3 planes), a Phillips PN 1710 diffractometric control unit, and Siemens / Socabin DIFFRAC / AT software. The exposure duration was 16 hours

CuKα radiation.

 Detailed description of reactors.

 1) Automated reactors.

 Two reactors were used with a maximum volume of 500 ml, containing 150 grams of glass beads with a diameter of 4 mm, acting as a filter for particles. Pumps and electrically operating valves ensured the automatic operation of the filling and suction system with alternating aerobic and anaerobic periods, and their operation was regulated by timers, while the reactors were subjected to three 8-hour cycles per day.

The inflowing medium and reactors were autoclaved before use while the pipes and valves were sterilized with 70% ethanol and washed with distilled water. Each 8-hour cycle looked like this:
Time (minutes).

 0-150 Incubation at the anaerobic stage (medium 4, nitrogen gas was bubbled through the medium at low speed to maintain the upper part of the space anoxic).

 150-161 Stage of absorption - medium 4 was eliminated, nitrogen was passed.

 161-166 Stage of filling - filling with medium 3 (aerobic medium), nitrogen was eliminated through the medium at high speed, air was sparged.

 166-464 Incubation at the aerobic stage, letting in air.

 464-476 Stage of absorption - medium 3 was eliminated, air was passed.

 476-480 Stage of filling - filled with medium 4, air was removed / nitrogen was passed through.

There were 3 anaerobic periods daily at the following times:
06.30-9.00, 14.30-17.00, 22.30-01.00. Samples were taken for analysis daily at the end of the first and second anaerobic periods, and, if appropriate, throughout the entire first aerobic and second anaerobic stages (09.00-17.00). No samples were taken during the third anaerobic stage.

 The approximate volume supplied to each reactor consisted of 200 ml of medium 4 for the anaerobic stage and 250 ml of medium 3 for the aerobic stage (inflow rate = 50 ml / min, efflux rate = 20.8 ml / min).

 For the analysis of phosphate and metal throughout the entire aerobic and anaerobic stages, 2-4 ml of a sample were taken with a syringe through a sampling tube. Before the analysis of the metal, the medium was allowed to settle, and for the analysis of phosphate it was centrifuged to remove suspended cells, and the pop-up was analyzed. Phosphate release during the anaerobic stage was determined as the difference between samples at the beginning and at the end of the anaerobic stage. To calculate the removal of metal, the samples of the effluent were allowed to stand for 5 minutes and the metal concentration was compared with the concentration of the inflowing medium.

 2) Column reactors.

 A variable-speed pump with manual reverse control and manually controlled valves provided an aseptic change in the medium between the aerobic and anaerobic stages. Column reactors were subjected to two anaerobic stages, each of which lasted 2.5 hours at approximately the same time every day (9.30-12.00 and 16.00-18.30). Glass beads (2 mm in diameter) were used as a filter at the base of each column. The total volume at each stage was 250 ml. During the change between stages, one medium was drained and the other medium was filled into the column in less than 5 minutes. For metal analysis, the settled effluent was compared with the inflowing medium. To the sample of residual phosphate in the column at the beginning of the anaerobic stage, by means of the first discharge of 10-15 ml of medium through a sampling pipe, a sample of the medium was taken to ensure the washing off of stagnant liquid in the sampling tube, then another 5 ml of sample was taken and subjected to centrifugation and analysis of the pop-up, the latter was compared with phosphate in the settled (supernatant) of the effluent.

 Experience 1. Comparison — inorganic precipitation of metal phosphates in a solution that does not contain cells.

Lanthanum nitrate (1 mM) and uranyl nitrate (1 mM) were incubated in the presence of 0.5 mM inorganic phosphate (as K ₂ HPO ₄ ) in medium 4 under a nitrogen sparge to ensure anaerobic conditions. From time to time, samples were removed, centrifuged (12,000 rpm, 5 minutes) and the surface that had surfaced was analyzed for the remaining phosphate and metal ions.

 FIG. 1a shows the rapid loss of lanthanum from solution due to precipitation of lanthanum phosphate. However, the precipitate is fine-grained and remains in suspension without centrifugation.

FIG. 1b shows that the uranyl ion (UO ₂ ²⁺ ) hardly gives a precipitate that can be removed from the suspension by centrifugation.

 Experience 2. The allocation of phosphate and metal removal using activated sludge that removes phosphate.

 Untreated activated sludge or the so-called “mixed liquid” was obtained from a Phostrip feed plant. The total suspended solid of the mixed liquid was 6.43 g / L. 350 ml of mixed liquid was used to inoculate each of the two automated reactors. It was covered (topped up) with 50 ml of medium 4 (without added metal) and the initial incubation of the anaerobic phase began. The reactors initially worked without metal in the inflowing medium 4, then, as shown in tables 1 and 2 below, cadmium or lead acetate (0.2 mM) or lanthanum nitrate (0.5 mM) were added.

 The results given in Tables 1 and 2 above are presented in the form of a diagram attached respectively in FIG. 2a and 2b.

 Experience 3. Comparison of the storage capacity of polyphosphate in strains W6 and W9 isolated from activated sludge, compared with the culture of the strain Acinetobacter calcaoceticus NCIMB 10694.

Cells were grown and harvested as previously described. A cell suspension containing approximately 1.0 g of cells (wet weight) was loaded onto pre-formed PercoII density gradients and centrifuged for 30 minutes at a speed of 9000 rpm. The cells formed a band in accordance with their density (specific density), which was determined with respect to the labeling beads (balls) of known density (the more polyphosphate, the higher the cell density), during subsequent incubation at 30 ^° C, the polyphosphate underwent degradation and was visible that the band of cells advances toward the gradient as the cells become less dense. Density reduction is a measure of short chain polyphosphate that can easily be degraded under anaerobic conditions.

 Experience 4. Removal of lanthanum by cell suspensions of Acinetobacter calcoaceticus NCIMB 10694.

A culture of Acinetobacter calcoaceticus NCIMB 10694 was harvested after 24 hours of development at an optical cell density (OD ₆₀₀ ) of 0.370. The wet weight of the obtained cell granule was 2.243 g and it was resuspended in a total volume of 6 ml. 1 ml of the suspension was added to the tubes containing 10 ml of each of the following solutions:
Tube 1: Medium 4 with 1 mM lanthanum nitrate, incubated aerobically
Tube 2 and 3: Medium 4 with 1 mM lanthanum nitrate incubated anaerobically.

 Tube 4: Medium 4 without metal, incubated anaerobically.

 Samples were analyzed as described previously.

 FIG. 3a shows that phosphate is released under anaerobic conditions, and not under aerobic conditions, less phosphate is apparently released in tubes containing lanthanum. FIG. 3b also shows the loss of lanthanum in tubes 2 and 3, which is accompanied by the release of phosphate. Significant removal of lanthanum was not observed in tube 1 under aerobic conditions, which indicated that there was a slight passive biosorption of the metal.

 Experience 5. Removal of lanthanum by cell suspensions of strain W9.

The strain W9 culture was harvested after 24 hours of development at a cell density (OD ₆₀₀ ) of 1,000. The wet weight of the obtained cell granule was 5.329 g and it was resuspended in a total volume of 6 ml. 1.5 ml of the suspension was added to tubes containing 20 ml of each of the following solutions:
Tubes 1 and 2: Medium 4 with 0.7 mM lanthanum nitrate incubated anaerobically.

 Tubes 3 and 4: Medium 4 without metal, incubated anaerobically.

 Samples were analyzed as described above.

 FIG. 4 shows phosphate release and lanthanum removal under anaerobic conditions with a concomitant loss of lanthanum and a clear decrease in phosphate release in the presence of lanthanum, followed by a sudden loss of phosphate release after 120 minutes. A decrease in the concentration of lanthanum (0.4–0.5 mM) observed after 210 minutes was combined with the release of 0.4–0.5 mM phosphate in the control tubes.

 Experience 6. Removal of lanthanum by cell suspensions of the selected strain W6.

The culture of strain W6 was harvested after 24 hours of development at a cell density (OD ₆₀₀ ) of 0.790. The wet weight of the obtained cell granule was 3.80 g and it was resuspended in a total volume of 6 ml. 1.5 ml of the suspension was added to tubes containing 20 ml of each of the following solutions:
Tubes 1 and 2: Medium 4 with 0.8 mM lanthanum nitrate incubated anaerobically.

 Tubes 3 and 4: Medium 4 without metal, incubated anaerobically.

 Samples were analyzed as described above.

 FIG. 5 shows phosphate release and lanthanum removal under anaerobic conditions with a loss of lanthanum and a sudden loss of phosphate released, which began after 60 minutes. It should be noted that the complete removal of 0.7-0.8 mM lanthanum occurred when 0.7-0.8 mM phosphate was detected in the control tubes (in the absence of metal).

 Experience 7. Removal of cadmium and lead in column reactors with immobilized cells of strain W9.

 The culture of strain W9 was grown and harvested as described previously and immobilized in agarose beads with an average diameter of 1 mm. The beads were placed in a pre-sterilized first and second column with a biomass load, the approximate wet weight of the cells of which was 5 g (100 g of gelled material) per column, although due to diffusion restrictions it was expected that not all cells in the beads contribute to the observed physiology of the immobilized culture, for example, diffusion restrictions for oxygen at the surface are typically 50 μm. Before introducing the metal, the columns were subjected to an anaerobic / aerobic cycle for 8 days in the absence of metal: approximately 0.2 mM lead acetate was introduced into the first column for 7 consecutive days, and approximately 0.2 mM cadmium acetate per anaerobic into the second column period. Samples were analyzed as described above.

 Table 3 below and FIG. 6 show the separated phosphate and certain lead in the inflow and outflow of the first column. Table 4 below and FIG. 7 show the separated phosphate and certain cadmium in the inflow and outflow of the second column.

 Experience 8. Removal of lanthanum and uranium in automated reactors with immobilized cells of strain W6.

 The culture of strain W6 was grown and harvested as described above, immobilized on agar, and the gel was crushed to obtain particles of approximately 1 mM x 1 mm x 10 mm. Particles were placed in pre-sterilized first and second column reactors with a biomass load, the approximate wet cell weight of which was 5 g (100 g of gelled material) per column. Before introducing the metal, the columns were subjected to an anaerobic / aerobic cycle for 7 days in the absence of metal: initially, 0.5 mM lanthanum nitrate was introduced into both reactors, then lanthanum was continued to be introduced into the first reactor, while 0.2 mM uranyl was introduced into the second reactor . Samples were analyzed as described above.

 At the end of the experiment, when the reactors were drained, they noticed that a biofilm had formed on the glass beads at the base of the reactors. The samples of the gelled material and the biofilm on the beads in the second reactor were pale yellow (uranyl phosphate is yellow) and it was seen that they fluoresce in ultraviolet light (as pure uranyl phosphate crystals do). Part of the gelled material and glass beads were shaken vigorously in acetone to remove surface bacteria and crystalline precipitate. The sample was dehydrated in acetone, evaporated and analyzed by x-ray diffraction.

 Table 5 below and FIG. 8 show the separated phosphate and certain lanthanum in the inflow and outflow of the first reactor. Table 6 and FIG. 9 show the separated phosphate and certain lanthanum and uranyl in the inflow and outflow of the second reactor. FIG. 10 and 11 show that there is no appreciable solubilization of the precipitated metals at the aerobic stage.

таких значений для H₂(UO₂)₂(PO₄)₂ • 8H₂O. Это указывает, что проба содержит кристаллический материал H₂(UO₂)₂(PO₄)₂ • 8H₂O.FIG. 12 shows that the spectrum obtained by x-ray diffraction of the sample from the second reactor is compatible with that obtained for H ₂ (UO ₂ ) ₂ (PO ₄ ) ₂ • 8H ₂ O (Ross (1955) Am. Mineral 40, 917-919 ) The d values for the 10 strongest diffraction peaks are respectively within 0.03

such values for H ₂ (UO ₂ ) ₂ (PO ₄ ) ₂ • 8H ₂ O. This indicates that the sample contains crystalline material H ₂ (UO ₂ ) ₂ (PO ₄ ) ₂ • 8H ₂ O.

Claims (7)

 1. A method of removing ions of one or more metals from water using a microorganism, characterized in that the polyphosphate-accumulating microorganism is cultured in a culture medium under conditions where the microorganism can synthesize and use adenosine triphosphate (ATP), modify the synthesis / use of ATP, whereby the microorganism uses polyphosphate as an alternative energy source, which leads to the production of phosphate ions, and these phosphate ions are reacted with metal ions to precipitate Veil metal.  2. The method according to claim 1, characterized in that the stage of cultivation is carried out aerobically, and the stage of modifying the synthesis / use of ATP is carried out by changing aerobic conditions to anaerobic conditions.  3. The method according to claim 2, characterized in that the interaction stage is carried out by introducing water containing ions of the specified one or more metals, after the aerobic stage of cultivation.  4. The method according to claim 2, characterized in that the microorganism is a bacterium of the genus Acinetobacter.  5. The method according to any one of claims 1 to 3, characterized in that the microorganism has polyphosphate-accumulating properties of Acinetobacter sp. W6 (NCIMB 40594) or Acinetobacter sp. W9 (NCIMB 40595).  6. The method according to any one of claims 1 to 4, characterized in that the cultivation step is carried out in the presence of activated sludge containing said microorganism.  7. The method according to any preceding paragraph, characterized in that said one or more metals is selected from cadmium, lead, uranium, lanthanum, lanthanides.

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